The aim of this R01 is to evaluate the impact of a local policy change (i.e., the Minneapolis Staple Food Ordinance) that establishes minimum stocking criteria for a wide array of healthy foods as a requirement of food store licensing. Recent calls to action from the Institute of Medicine, the Centers for Disease Control and Prevention and other authorities have identified improving access to healthy foods as a primary strategy for local governments to use in advancing obesity prevention efforts, but policy initiatives in this area have been limited. In this R01, the impact of the Minneapolis Staple Food Ordinance will be evaluated by assessing objectively measured changes in: (a) food environments among small, urban food stores, including availability, promotion, advertising, quality, price, and placement of both healthy and unhealthy foods and beverages, (b) nutritional quality of consumer purchases at small food stores, including assessment of energy density and calories via customer intercept surveys and direct observation of purchases and (c) home food environments, including availability of healthy and unhealthy foods/beverages and an overall home food obesogenicity score, among households that frequently shop at small stores. These changes will be assessed pre-policy implementation, as well as 4-, 12- and 24-months post-policy implementation, in two Minnesota cities: Minneapolis and St. Paul, (our control community). The proposed scope of work in this R01 is important because its takes advantage of a unique opportunity to evaluate an innovative local policy addressing a recommended action area for obesity prevention that aligns with key recommendations by leading obesity prevention authorities. To our knowledge, the Minneapolis Staple Food Ordinance is the only policy of its kind in the US, and as such it could serve as an important model policy for other local governments if it is successful.